A wide variety of medical treatments utilize the delivery and introduction of therapeutic compositions to a treatment location in a patient. In home or outpatient settings, the delivery methods used can include procedures such as oral delivery or inhalants, while in clinical or hospital types of settings, a therapeutic fluid is often injected using a needle-based system. In more complicated methods, a fluid can be delivered surgically through a tubular device, such as a catheter or endoscope, and in some cases, the surgical method can involve minimally invasive procedures.
For minimally invasive procedures, a number of systems have been developed for delivering therapeutic fluids to treatment sites within a patient that include minimally invasive, tubular delivery lumens (e.g., catheters or endoscopes) and pressurized fluid sources. In some cases, these fluid sources include a syringe-like structure that is actuated by a plunger. This plunger can be controlled via a console having control features that help the user to control the amount of pressurized fluid that is delivered to and/or expelled from the system. These systems can include needleless fluid injection systems, for example. Needleless devices and methods for treating tissue of the urinary tract are discussed, for example, in U.S. Patent Application Publication No. 2009/0312696 (Copa et al.), and U.S. Patent Application Publication No. 2006/0129125 (Copa et al.), the entire disclosures of which are incorporated herein by reference. One particular application for needleless fluid delivery systems is for treatment of diseases of the prostate, such as prostatitis, benign prostatic hyperplasia, and prostatic carcinoma.
Needleless fluid delivery systems can include the use of a tube-like device, such as an elongated catheter tube, which is configured to provide a jet-injection of a therapeutic fluid at a desired treatment site. Generally, a needleless injector is used to deliver the therapeutic fluid that is provided from an external reservoir that is located at a proximal end of the tube-like device. The actual fluid administration occurs at a distal end of the tube-like device. Due to the relatively long travel length of the therapeutic fluid through the tube-like device, an injector must generally be capable of pressurizing the therapeutic fluid to a relatively high pressure in order to achieve a certain desired fluid delivery pressure at the distal end of the device.
For any injection or injected tissue, therapeutic agents are desirably delivered with minimal discomfort and procedure time, and with the best possible degree of accuracy of delivery location and delivery volume, and with uniform and accurate distribution of a fluid throughout injected tissue. Further, due to the characteristics associated with the delivery of therapeutic compositions to treatment locations in a patient, there is a need to provide improved procedures, systems, and components for fluid delivery using needleless fluid delivery systems. Such procedures, systems, and components can provide for accurate and controlled dispensing of therapeutic compositions to specific treatment locations within a patient. In particular, there exists a continuing need to provide improved devices for delivering therapeutic fluids to different tissues such as locations of the urinary tract including the bladder, bladder neck, prostate, urethra, kidneys, and ureters.